A large amount of research has been conducted over the years related to developing treatments against cancer and viral diseases. Some of this research has been successful in finding clinically approved treatments. Nevertheless, efforts continue at an ever-increasing rate in view of the extreme difficulty in uncovering promising antiviral and anticancer treatments. For example, even when a compound is found to have antiviral or anticancer activity, there is no predictability of it being selective in humans against virus or cancer cells.
Of the DNA viruses, those of the Herpes group are the source of the most common viral illnesses in man. the group includes herpes simplex virus (HSV), varicella zoster virus (VZV), and cytomegalovirus (CMV). Most of these viruses are able to persist in the host cells; once infected, individuals are at risk of recurrent clinical manifestations of infection, which can be both physically and psychologically disabling. Infections with human cytomegalovirus (HCMV) are apparently ubiquitous in the general population. The virus may produce an acute disseminated infection in neonates and such generalized infection is often fatal. Congenital infections in children with HCMV may result in neurological damage and may later result in severe auditory defects and mental retardation. While infection is usually asymptomatic in normal adult individuals, primary HCMV infection or reactivation of latent HCMV invention can cause serious, life threatening disease in immunosuppressed patients.